Spatial Variability in Seawater pCO2 Associated with Biology

The first annual-scale estimate of the cycling of carbon dioxide in the coastal waters of the Gulf of Maine has been made with our underway pCO2 measurement system on monthly UNH Gulf Challenger cruises from 2004- present (Vandemark et al. 2006). Results show the region to be a net sink of this greenhouse gas at a level exceeding that cited for the Mid-Atlantic Bight and they also indicate high interannual variability mostly attributed to freshwater dynamics. The figures below provide one example of the spatial variability that we encounter on a given cruise (Aug. 16, 2005). Here the temperature, dissolved oxygen, carbon dioxide and fluorometric chlorophyll estimates inside the box all indicate a local upwelling just inside of Jeffrey's ledge, a local event where the data, when combined, are strongly indicating that patch of phytoplankton is growing in this area. Such observations, both seasonal and spatial, are critical to predictive models showing how the U.S. and other coastal regions affect the overall budget of greenhouse gases over the North American continent and the globe.